From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Szyprowski Subject: Re: [PATCH RFC v2 08/12] soc: samsung: pm_domain: Add support for parent power domain Date: Wed, 03 Dec 2014 09:36:27 +0100 Message-ID: <547ECB8B.3040905@samsung.com> References: <1416833572-6880-1-git-send-email-amit.daniel@samsung.com> <1416834256-11225-1-git-send-email-amit.daniel@samsung.com> <1416834256-11225-8-git-send-email-amit.daniel@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-reply-to: Sender: linux-samsung-soc-owner@vger.kernel.org To: Geert Uytterhoeven , amit daniel kachhap Cc: Ulf Hansson , "devicetree@vger.kernel.org" , Kukjin Kim , Kevin Hilman , Pankaj Dubey , "linux-pm@vger.kernel.org" , "Rafael J. Wysocki" , "linux-kernel@vger.kernel.org" , linux-samsung-soc , Sylwester Nawrocki , "linux-arm-kernel@lists.infradead.org" List-Id: linux-pm@vger.kernel.org Hello, On 2014-11-25 10:19, Geert Uytterhoeven wrote: > On Tue, Nov 25, 2014 at 9:57 AM, amit daniel kachhap > wrote: >>>> diff --git a/Documentation/devicetree/bindings/arm/exynos/power_domain.txt b/Documentation/devicetree/bindings/arm/exynos/power_domain.txt >>>> index 00ebda1..0160bdc 100644 >>>> --- a/Documentation/devicetree/bindings/arm/exynos/power_domain.txt >>>> +++ b/Documentation/devicetree/bindings/arm/exynos/power_domain.txt >>>> @@ -24,6 +24,7 @@ Optional Properties: >>>> - pclkN, clkN: Pairs of parent of input clock and input clock to the >>>> devices in this power domain. Maximum of 4 pairs (N = 0 to 3) >>>> are supported currently. >>>> +- parents: phandle of parent power domains. > Why not using just "power-domains = <&pd_top>"? > This is consistent with how clocks refer to their parent clocks. I agree. The only question is weather exynos dts should keep using samsung,power-domain property, or switch to generic 'power-domains' approach. I assume that exynos-pm driver should support both. >>>> Node of a device using power domains must have a samsung,power-domain property >>>> defined with a phandle to respective power domain. >>>> @@ -48,6 +49,7 @@ Example: >>>> mfc_pd: power-domain@10044060 { >>>> compatible = "samsung,exynos4210-pd", "samsung,exynos7-pd-mfc"; >>>> reg = <0x10044060 0x20>; >>>> + parents = <&pd_top>; >>>> #power-domain-cells = <0>; >>>> }; >>> This seems like a good and generic approach to describe that a PM >>> domain could have a parent. I would suggest to rename it, such it >>> reflects its a PM domain binding though. >> I am not sure if this is generic. I guess PD's represented like below >> are more generic. >> PD1 { >> PD2 { >> PD3 { >> }; >> }; >> }; > Such a representation is not always possible. > If you have one power-controller for a hierarchy of PM domains, you can > use it. > If you have multiple power-controllers, the power controller nodes are at the > same level in DT, so you'll have to use "power-domains" properties to link > them together. I agree. I will send updated patch for this purpose for existing exynos4 power domain driver. Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland From mboxrd@z Thu Jan 1 00:00:00 1970 From: m.szyprowski@samsung.com (Marek Szyprowski) Date: Wed, 03 Dec 2014 09:36:27 +0100 Subject: [PATCH RFC v2 08/12] soc: samsung: pm_domain: Add support for parent power domain In-Reply-To: References: <1416833572-6880-1-git-send-email-amit.daniel@samsung.com> <1416834256-11225-1-git-send-email-amit.daniel@samsung.com> <1416834256-11225-8-git-send-email-amit.daniel@samsung.com> Message-ID: <547ECB8B.3040905@samsung.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hello, On 2014-11-25 10:19, Geert Uytterhoeven wrote: > On Tue, Nov 25, 2014 at 9:57 AM, amit daniel kachhap > wrote: >>>> diff --git a/Documentation/devicetree/bindings/arm/exynos/power_domain.txt b/Documentation/devicetree/bindings/arm/exynos/power_domain.txt >>>> index 00ebda1..0160bdc 100644 >>>> --- a/Documentation/devicetree/bindings/arm/exynos/power_domain.txt >>>> +++ b/Documentation/devicetree/bindings/arm/exynos/power_domain.txt >>>> @@ -24,6 +24,7 @@ Optional Properties: >>>> - pclkN, clkN: Pairs of parent of input clock and input clock to the >>>> devices in this power domain. Maximum of 4 pairs (N = 0 to 3) >>>> are supported currently. >>>> +- parents: phandle of parent power domains. > Why not using just "power-domains = <&pd_top>"? > This is consistent with how clocks refer to their parent clocks. I agree. The only question is weather exynos dts should keep using samsung,power-domain property, or switch to generic 'power-domains' approach. I assume that exynos-pm driver should support both. >>>> Node of a device using power domains must have a samsung,power-domain property >>>> defined with a phandle to respective power domain. >>>> @@ -48,6 +49,7 @@ Example: >>>> mfc_pd: power-domain at 10044060 { >>>> compatible = "samsung,exynos4210-pd", "samsung,exynos7-pd-mfc"; >>>> reg = <0x10044060 0x20>; >>>> + parents = <&pd_top>; >>>> #power-domain-cells = <0>; >>>> }; >>> This seems like a good and generic approach to describe that a PM >>> domain could have a parent. I would suggest to rename it, such it >>> reflects its a PM domain binding though. >> I am not sure if this is generic. I guess PD's represented like below >> are more generic. >> PD1 { >> PD2 { >> PD3 { >> }; >> }; >> }; > Such a representation is not always possible. > If you have one power-controller for a hierarchy of PM domains, you can > use it. > If you have multiple power-controllers, the power controller nodes are at the > same level in DT, so you'll have to use "power-domains" properties to link > them together. I agree. I will send updated patch for this purpose for existing exynos4 power domain driver. Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland